Preparation of straight chain hydroxy compounds having at least six carbon atoms



' cohols by catalytic hydrogenation.-

' Patented Nov. 23,1943

"' UNITED; STAT DROXY COMPOUND ES; PATENT germs I answer v or STRAIGHT s HAVING'AT nnssr.

SIX CARBON ATOMS William E. Hanfordl Wilmington, DeL, Nemours & 'poration of and Richard S. Schreiber, assignors to E. I. du Pont de Company, Wilmington, Del, a cor- Delaware I No Drawing. .dppllcationflctober-tm;1939,

Serial No. somsz ,5 (dissipate) This invention relates to the preparation of straight chain hydrow compounds having at least 6 carbon atoms. More particularly it relates to the preparation of trihydroxyhexane and tetrahwdromoctane. It also relates to the preparation I 6 scope of this invention.

. The following examples set forth certain well defined instances ofthe application of thisinventitan.- They are, however, not to beconsidered aslimitations thereof since many modifications may be made without departing-from weep ng and Em i; Eleven were added 63 grams of barium hydroxide octa= I hydrate ,(Ba(OH)2..8HaO) dissolved massed-oi ponents of the reaction mixture, or for their lsolation in substantiallwpure form. 'It has now been unexpectedly discovered that the reaction may be controlled at any desired degree of condensation by converting the resulting polyhydroxy aldehydes to the corresponding polyhydroxy alalcohols may then be isolated'fromthe reactionmixture and separatedfrom one another either warm water. After agitating thesolutiori vigorous'ly. for 2 hours, the total aldehyde content had dropped to approximately one-fourth of the v original value. The temperaturcrose from C.

- to 40 C. duringthis period. At this'point, fur- The resulting 20 by vacuum fractional distillation or by any other means known to the art.

This invention has as an object the provision. with ether n distilled undqr d ced P of a new and simple process for the production of straight chain hydroxy compounds having at least 6 carbon atoms. Another object is the tion of trihydrom hexane and tetrahydroxy oc-' .tane. Still another object is the production of polyhydroxy aldehydes having at least 6 carbon atoms. Another object is to provide a method of hydrogenating hydrowaldehydes to the cone-1 p e a e sponding hydroxy; derivatives "having one more primary hydroxy group than the parentalde- 'hydes. Another object is to provide new chem-- ical compounds. Other objects will be apparent from a reading of the following. description of the invention.

These objects may be accomplished by a procas involving one or more' of the following steps. An aldol is condensed with acetaldehyde or with itself in the presence of an alkaline ca st and the primary product obtained is catalyti y hy-. .drogensted' so as to convert the aldehydegroup,

I to a primary hydroxy group. The polyhvdroxy compounds obtained in the condensation step have hydroxy groups on alternate carbon atoms ther reaction was prevented by" neutralizing the solution with sulfuric acid. The.i esulting*yellow,.

viscous solutionwas then catalytical'lyhydrogenated latto .150 C; using gramsof nickei .1

on-kieselguhr catalystand a pressure-of 2,000 to 3,000 lbs. per square inch". v After filtering ofi the catalyst, the hydrogenated material was extracted sure to yield the following results;

The tetrahydroxyoctane obtained by pro Fraction LGIQIHS I ti? i T Tiihydi-oryhexane. 290 216 Tetrahydroxyoctane.

- cedure.is a straw-colored. viscous liquid ,.extreme 1y soluble in water, somewhat hysroscopimand insoluble in ether. This material-was analyzed to give the following results 0, 54;.90; 11,1 0.05; moi.

' wt-., 191; hydroxyl number, 1175'.

with an aldehyde group on one of the terminal carbon atoms. A preferred embodiment of this process comprises carrying out the condensation of gidoi with itself in such a. manner-that high.

yields of atrihydroxyectanal are produced, 'and' corresponding tenahydroryoctane.

" Onehundred The trihydroxyhexane is also a straw-co ored butnot quite as viscous a liquid, extremely ol uble in water, and insolublein ether. Analysis of this fraction gave the following'resultsz'c, 53.90; H, 10.80;;mol. wt.,118;- hydroxylnumber, 1o77.w

semen II 25 cc. of"? 50% solution of sodium hydroxide was rapidly to approximately 25-35 C. After one catalyticallyhydrogenating this aldehyde to the I hour at this temperature-25 co. more of50%'- hundred fifty grains of para'ldol were dissolved in l liter of water, and to this mixturethirty-two grams of paraldol were a partially dissolvedin cc. of water, and then .hydroxidehydrate (Ba(OI H)2.8HaO). The addipressure, the following results were obtained:

.' a Boiling -Pmssum Fraction Grams pgirt, mmm; Substance I 100-110. 8 Butylene glycol. 110-150 3 r 150-160 3 Trihydroxyhexene'.

200-210 3 Tetrahydroxyoctane.

I .Analysis of Fractions III and IV gave results similar to those'described in Example I.

- p 1 Example In g 'Five hundred grams of crude aldol were treated with'50 cc. of water containing 10 g.-of barium tion of this alkali raised the pH from 6.8 to 9.7. After 18 hours, during which time the temperature was held at -33 C.-,the total aldehyde content had dropped to approximately one-half the 3 ori j alvalue; At this point, suflicient sulfuric acid was added to lower the pI-I to 6.5, and then one-half of this mixture was hydrogenated similarly to that described in Example I. Distillation of the hydrogenated product yielded the fol- 3 lowing results:

C9 V Bomilg Pressur Fraction Grams pgiit, in Substance {105-110 -a Butylene g1 col.

II 150-160 2 'lrihydroxy xane. .111 200-215 2 Tetrahydroxyoctaney Analysis of Fractions II and III gave results similar to those described in Example I.

Example IV I Three hundred grams of pa dol were dis solved in300' g. of water by ad g 3 cc. of dilute 1.0% sodium hydroxide and warming to C. At this point, 20 g. .of magnesium oxide were added, and the-soluti n vigorously agitated. for 24 hours while maintainingia temperature of 40 C. At the end of this time, the total aideh d content had dropped to'approxiznately 'oneof the-original value. After filtering to re the unchanged catalyst, the solution was neutralized by adding dilute sulfuric acid and then ap- F proximately one-third washydrogenated in the -manner described .Example I, using 15 g. of nickel-on-kieselguhr' atalyst. After separating the oily layer whiclg gumounted to approximately 33 g., the residue was distilled under reduced pressure to yield the follojjing results:

Grams t gt gfif a Substance Butylene glycol.

Trihydrohexane. I Tetrahydroxyoctane.

Analysis of Fractions III and IV ga ve results similar to those obtained for the corresponding compounds in Example I.

methyl ethe Example V One hundred grains of'paraldol were partially dissolved in 100 cc. of dioxane. -To this slurry were added 2 g. of powdered calcium oxide, but 5 as no appreciable increase lution was observed, 16 cc. of 10 ,s,odiur n hydroxide were added. The addition of thisamount of alkali raised the pH from 6.5 to 8.5. After 2 hours at 30-35" C., during which agitation was maintained, thetotal aldehyde content liad dropped to one-quarter of theXoriginal value. The solution was then treated with suflicient sulfuric acid tolower the pH to 6.0, and the sample hydrogenated with 10 g. of nickel-on- V15 .kieselguhr, using conditions similar to those em- A ployed in Example I'.- After removal of the catalyst and dioxaneqthe residue was distilled at 4 to 5 mm. pressure to yield the following results:

Substance Grams -140 -160 Trihydroxyhexane.

hexanal which on hydrogenation produces ,the trihyfioxyhexane as indicated in Examples I, II, 5 III, and V. Due to the fact that both triliydroxyhexane andtetrahydroxyoctane contain two or more asymmetric carbon atoms, several stereoisomers are to be expected which would readily account for the very wide range in the boiling oint of the pure product. v

It is not essential to start with paraldol orpure aldol since the crude aldol as obtained by the condensation of acetaldehyde with itself wilLserve equally well for this purpose. In the practice of 5 this invention it is generally preferred to use aldol concentrations in the-range. of -40.to 50%, I because above about 50% the rate of condensation is retarded and concentrations below about 40 are uneconomical.

Although the reaction can be carried out in water or in inert! organic solvents in which aldol or paraldol is soluble, water is the preferred solvent. In place of water there may be used such organic solvents as ethanol, dioxane, butanol, of ethylene glycol, benzyl alcohol,

, chloroform 6 v Any strong-alkaline catalystwill cause-aldol to condense'with itself to give the desired products. The preferred condensing agents are the oxides 0 or hydroxides ,of the alkali or alkalineearth elements such as sodium, potassium, calcium, magnesium, and barium. Due to the fact that acidic compounds are produced in small amounts during the condensation, it is usually necessary 1;: 65 use at least three per cent catalyst based on thl aldol employed. In actual practice amounts o1 catalyst ranging from 3% to 10% based on th weight of aldol should beqised. 1

Although temperatures ranging from 0 C. u to 150 C. can be employed, it is preferable to us temperatures ranging between 25 and 15 11 better control duringithe con order to obtain -densation step.

in the pH of the sotime vigorous 200-215 Tetraliydroxyoctane.

dense with the aldol and give rise to a dihydroxybased on the aldol employed. In

materiele.

- and eceteldehyde in the presenceoi ostolyst, inon aqueous medium at when the totel aldehyde content has dropped to stopped almost completely by cooling the mixture to temperatures below 0., it is preferred to treat the mixture yzith an inorganic or organic acid until the DH has been lowered in the range of 5.0 to; 6.5.

For -hydrogenatingjmcondensotion products any of the'common hydrogenation'catalyeta can be used, but it is generally preferred'touse e ierrous metal cstolyot ouch on metallic nickel or coho-1t either in a massive form. or eupportedon such materials or hiecelouhr or silica gel. lhe amount of catalyst required ranges from 1 to ueneroi the quantity. of catalyst end conditions of hydrogenaionore largely dependent on the type of catalyst tact'with a hydrcoenaticn mixture with hydrogen at a temperature within to a value used. in place -oi the ferrous-motel cetalyote there may be used mild ectine hydrogenation catalysts such etc., their oxides end chromites, end the oxides and chromites of manganese, iron, nickel, cobalt.

etc. In the hydrogenation stop. temperatures in the range of C. to 200 C. preferred, however, to carry tion at temperatures in the 150 C. Hydrogen preosureo limited only by the bursting strength of the reection vesselueed they may he used. It it out the hydrogenu= be employed. It is generally preferred to employ pressures rongingirom 1090 to $000 Ibo/ed in.

are silver, tin, cedmium,.copper,-

range of 50C. to

The polyhydric alcohols oi thic invention. are

useful or elycerine substitutes, especially as phas ticizers and ingredients for the preporotion oi polyhydrio elcohol-polycerboxylic uciti retiihe.

By this process new types of polyhydric elcoholo from inexpensive rew can be readily obtained It is apparent that many widely dirtiest em bodlmente of this invention may be made without departing from the spirit andscope thereof and 7 therefore it is not intended as indicated in theappended claims. t

We oieim:

lfll'he process for the production of watersoiubie trihydiio end higher polyhydrio alcohoio which oomprioee condensing eldol with a memberseleotediron: the close consisting of aldol an alkaline s tempera.- ture between 0" G.

to be limited except i and 150 Q. and maintains:

. pereture within the more of C. to

me cold condensation reaction until approxi matelr oneheir to three-iourtho oi the totel, aldehyde has been condensed, then etopping the condensation reaction, thereby ture of ureter-eoluble otreiejhtwhein pclyhydroxy aldehyd ee oi at least 6 carbon atoms having on aldehyde oro upon e terminal carbonatcm and howling a hydrony group on alternate carbon f obtaining o. misc,

i m catalyst while in adatome, hrinzinc the resulting mixture into carried out at a temperature within the *rence of 60 to MPG. while mine it i hydrogenation catalyst selected from.- the group consisting of nickel. end cobalt hydrogenation oatelysth- 3. A process for the production oi water eoluhie trihydric end higher polt'htdrio elooholc which comprisee condensing aldol with e rnem= her selected from the close conciotinn oi cldol end ecetoldehyde in the presence oi onolhuline cetelyet', in on edueouo medium, at d temperat -ture between 25 0. and it 0., end moihtninino ooid condensation reaction until epprootely one-half to three-fourths of the total aldehyde has been condensed thereby obtaining o, mixture of woter-ooiuhie straight chain polyhydroxy eldo hydes or at letet 6 carbon etcrno havinmon oide= hyde grouper: e terminal carbon atom and hov ino hydrortyi groups on olternate carbon dioxide, eddihg on ocid to sold reactants in a quantity suficient to reduce the pi-i oi the solution to from ture with hydrogen under at pressure within the range or 1000 to 4.000 lbs. peer to. in. end otlgote g *0 thereby hydrooenating ooid straight chain polyhydrous; oldehrdes to the correopondine elcohol. t. Ehe process in accordance with cleim ti characterized in that the eldehyde concentrat tion inthe starting meteriel prior to time iowithi'n the range-of to to 50%. e

6. A process ior'the production of weter oolm hie otroioht chein poiyhydrouy oldehlldes of at least .6 carbon atoms having on aldehyde group on eterminei carbon etom end hevino' ht'drouyl groups on alternate carbon. atoms which corn;-

prisee condensing aldol with from the group consisting of aldol end eceteldehyde in the presence oi an alkaline catalyst, in an aqueous medium, at o temperature within the renge of 25 to 76" 6.. ondotoppinothe reaction when approximately. one-half to threefourths of the total aldehyde has been condensed by adding thereto on acid in quantity suficient to reduce the pH oi the solution to from 5.0 to 6.5. m. RIG o 8. SCHREIBER.

that the catalytic hydroaena- 5.0 to 6.5, and bringing sold resulting nurture into contact with condonede. inemioer eeleoted j 

